Field
The disclosed concept pertains generally to vacuum switching apparatus and, more particularly, to vacuum switching apparatus such as for example, vacuum interrupters. The disclosed concept also pertains to contact assemblies for vacuum switching apparatus. The disclosed concept further pertains to methods of securing an electrical contact to an electrode in vacuum switching apparatus.
Background Information
Some circuit breakers such as, for example, power circuit breakers, employ vacuum interrupters as the switching devices. Vacuum interrupters generally include separable electrical contacts disposed on the ends of corresponding electrodes within an insulating housing. The electrical contacts are typically mechanically and electrically connected to the electrodes by brazing. While further components of the vacuum interrupter are being assembled with the electrode/electrical contact assembly, it is important to keep the mating between the electrode/electrical contact secured. Known practices for securing this connection involve employing a contact weight on top of the electrical contact. However, employing a contact weight has disadvantages. For example, while the vacuum interrupter is brazed in a furnace, the contact weight requires an additional expenditure of energy by the furnace. Additionally, employing a contact weight creates a risk that the electrical contacts will not be properly positioned, which can result in poor brazing of the joint between them, leading to an undesirable increase in electrical resistance of that joint and of the entire vacuum interrupter. There are also situations when the use of a positioning weight is prohibited, for example and without limitation, when the entire vacuum interrupter is to be brazed in a single vacuum brazing furnace run.
There is, therefore, room for improvement in vacuum switching apparatus, and in contact assemblies and methods of securing an electrical contact to an electrode therefore.